If you want a 6pack you should take the time to research how to train yourself and not ask someone to give it to you because you will not understand what you are doing.

Nobody except for you can know what will be an effective protocol to give you a sixpack.

If you are overweight, then improve your diet and exercise regime.

If you are already pretty fit and just need more definition, then improve your diet some more and do weighted ab work along with a routine that covers the rest of your body.

Due to genetics some people will never have a sixpack so if you do the above for a few years with great dedication and still dont get one then, perhaps it is time to set some new goals and be happy with who you are.